An era stretching more than 50 years came to an end July 31, as the last T-37 Tweet trainer departed Sheppard Air Force Base, Texas, bound for the "Boneyard" at Davis-Monthan Air Force Base, Ariz. Since the Tweet became operational in 1957, more than 78,000 fliers from the Air Force, NATO allies, and other countries used it to earn their wings. It is replaced by the T-6 Texan II.